Esters of sulphodicarboxylic acids



Patented Jam-14, 1936 ESTERS OF SULPHQDIQABBOXYLIC ACIDS Alphons 0.Jaeger, Greentree, Pa., assignor, by mesne assignments, to AmericanCyanamid & Chemical Corporation, New York, N. Y., a corporation ofDelaware No Drawing. Application July 28, v1933, Serial No. 682,629

14 Claims.

This invention relates to new esters of aliphatic sulphodicarboxylicacids and to a new method of producing such esters.

Esters of sulpho saturated and unsaturated aliphatic dicarboxylic acidssuch as, for example, mono and disulphosuccinic, sulphochlorsuccinic,

sulphoadipic, sulphopyrotartaric, sulphoglutaric,

sulphosuberic, sulphosebacic, sulphomaleio, sulphofumaric,sulphodimethylsuccinic, suphomethylglutaric, sulphopcmelinic,sulphoprypylsuccinic, sulphooctylglutaric, and other sulphonateddicarboxylic acids of the aliphatic series have never been preparedhitherto. These esters, particularly in the form of their alkali'forming metal salts, are of great importance in industry by'rea- 1 sonof their extraordinary wettingpqwers in various aqueous and organicsolutions emulsions or suspensions. They .are also of importance asdetergents, emulsifying agents, and the like.

A list of a few typical uses for the esters of the present invention arethe following: emulsifying agents; aids in carbonizing; washing agents;

dye assistants; dispersing agents in making emulsions and dispersions ofvarious chemicals, such as emulsions of hydrocarbons of various groupsof the aliphatic and aromatic series; terpene emulsions; wettingcompositions in emulsified form; dispersing agents in making emulsifiedgermicides; color lakes; dye preparations boring oil; drilling oils;emulsions of various animal and vegetable fats and oils; greasingcompositions in emulsified form; lubricating compositions containingvegetable or animal fats and oils; solvents for fats in emulsified form;wetting compositions containing oils in emulsified form; wire-drawingoils-in emulsified form; printing inks; writing inks; insecticidalpreparations in emulsified'form; emulsified dressing compositionscontaining various substances such as shellac, gums, natural andsynthetic resins, fats and oils; emulsified fat liquoring baths;emulsified finishing compositions; emulsified soaking compositionscontaining neats-foot oil or otheroils to be used as leather fatliquors; emulsified waterproofing compositions; automobile polishes;cleansing compositions containing soaps; compositions for cleansingpaint and metal surfaces; degreasing and greasing compositions inemulsified form; detersive and scouring compositions; furniture pol- 0ishes in emulsified form; metal polishes in emulsified form; scouringcompositions for woodwork, linoleum, rugs, and 'the like; shoe creamsand polishes in vemulsified form; waterproofing compositions inemulsified form for treating miscellaneous fibrous and othercompositions of matter; coating compositions for oilcloth and linoleum;asphaltic paints and varnishes; emulsified paints and varnishes; pigmentemulsions;

shellac emulsions; emulsified preparations used for the treatment ofpaper and pulp products; 5

A sizing compositions in emulsified form containing rosin, casein,starches and the like; waxing com positions in emulsified form; creamsin emulsified form; emulsified shampoos; lotions; latherless shavingcreams; various emulsified perfumes and 10 cosmetics; emulsionscontaining petroleum or heavy petroleum distillates; emulsified cuttingoils for lathe and screw-press work; kerosene emulsions; naphthaemulsions; soluble greases in emulsified form; soluble oils inemulsified 15 form, for lubricating textile machinery; variousemulsified te'xtile oils; rubber compositions in emulsified form;special emulsified preparations used for coating, projecting, decoratingand other surface treating of rubber mechandise; hand- 2 cleasingcompositions in emulsified form; various emulsified cleansing andsecuring compositions containing soap; dressing compositions inemulsified form; dispersions used for degreasing and washing raw wool;emulsified preparations for 25 degumming silk; emulsions for soakingsilk; emulsified mercerizing baths; special lubricating compositionsused in weaving, knitting, warping and winding; emulsions for fireextinguishers; emulsions for the preservation and impregnation of wood;and emulsions for mordanting.

The esters may be prepared by esterifying the sulpho acids, which acidsmay be prepared either by sulphonating the unsulphonated saturated acidor by adding a sulphite or bisulphite to the corresponding unsaturatedacid or its salts. Another method of producing, the sulpho acid is totreat the halogenated saturated acid with an alkali sulphite preferablyunder pressure.

While the present invention in its broad aspects of new esters as newchemical compounds is not concerned with the particular method by whichthe esters are prepared, in a more specific aspect an improved processof comparing the esters is included. This process consists in esteri- 5fying the corresponding unsaturated acid and adding a bisulphite to theester. This process presents marked advantages over the alternativeprocess of esterifying the already prepared sol pho acid, since theunsaturated acid is practically in all cases more easily esterifiedand'inthe form of the ester can be readily purified where it is desiredto produce a relatively pure product from a crude unsaturated acid. Thisis of particular importance in conjunction with the pro- 5 duction ofesters of sulphosuccinic acid because the raw material, maleic andiumaric acids, can be readily obtained in a somewhat crude form as abyproduct from the manufacture of phthalic anhydride, by the catalyticoxidation of naphthalene. As the esters of sulphosuccinic acid can bemanufactured very cheaply and show extraordinary powers as wettingagents and emulsifying agents and are commercially of prime importance.the preferred process is of special economic value in conjunction withthe production of esters of sulphosuccinic acid.

The esters of the sulphoaliphatic dicarboxylic acids are of the mostvarious types. Thus, for example, esters of low molecular alcohols suchas methyl and ethyl and propyl alcohols, are very soluble in water inthe form of their alkali metal salts, and form excellent detergents.Esters of higher molecular alcohols show increasing powers as wettingagents, but in general with a decreasing solubility in water in the formof their alkali-metal salts. Thus'the butyl esters show considerableincreased wetting powers over the propyl ester and the diamyl estersshow extraordinarily high wetting powers and still have excellentsolubility in water. These amyl esters may be single esters such asnormal amyl, isoamyl, or secondary amyl esters; or mixed amyl esters maybe obtained by esterifying with the mixture of amyl alcohols obtained bythe hydrolysis of halogenated pentane fraction of natural as and soldunder the trade name of Pentasol. Even higher wetting power is obtainedwith esters of the various octyl alcohols, such as, for example 2 ethylhexyl alcohol and capryl alcohol.

Alcohols of still higher molecular weight are of importance as wettingagents and particularly as emulsifying agents where the solubility inwater is not of prime importance. Typical examples are, lauryl estersand stearyl esters. The esters may be prepared from the pure alcohols orfor most purposes it is sufficient to use the technical grade of mixedalcohols obtained from the reduction of various fats and fatty acidmixtures. I

In addition to the monohydric parafiin alco .hols, various etheralcohols are of importance such as, for example, the ethers of ethyleneglycol, for instance, the methyl, ethyl, butyl, amyl,

' ethers, etc., which are readily obtainable in the trade. Ethers ofdiethylene glycol such as the methyl, ethyl or butyl ethers are likewiseof importance and produce esters which are valuable wetting agents anddetergents. The invention is in no sense limited to esters of aliphaticmonohydric alcohols but includes also esters of cyclic alcohols andphenols which are of importance for many purposes. Thus, for example,benzyl esters, esters of phenol, cresols, xylenols, naphthols and thelike, are included in the invention. Alicyclic alcohols such ascyclohexanol, methylhexanol, likewise form esters having important anduseful properties. Esters of various terpene alcohols are also included,such as borneol, fenchyl alcohols, menthyl alcohols, and the like, canbe prepared and are included.

Heterocyclic alcohols also form esters with desirable properties.Examples of typical heterocyclic alcohols are furfuryl alcohols,tetrahydrofurfuryl alcohol, and the like. Alcohols of various types mayalso be used.

In addition to the esters in which two molecules of the same alcoholunite with the carboxyl groups of the dicarboxylic acid, a series ofvery important esters can be obtained in which one carboxyl group uniteswith one alcohol and miother carboxyl group unites with a differentalcohol. These mixed esters are particularly important where it isdesired to obtain some of the valuable wetting andemulsifying-properties of high molecular alcohols, such as, for example,

.lauryl and stearyl alcohols, without sacrificing to too great an extentthe water solubility of their alkali metal salts. Thus, for example, themixed ethyl-lauryl and methyl-stearyl esters of a sulpho acid such assulphosuccinic or sulphoadipic acid possess many of the properties ofthe dilauryl or distearyl esters but are considerably more soluble inwater. Obviously of course, the

' number of mixed esters which can be produced is ular, it should beunderstood that the invention is in no sense in this particularmodificationto mixed esters in which one alcohol is high molecular andthe other low. Thus, for example, very desirable mixed esters may beobtained in which the two alcohols are or comparable molecular weight.Such esters are, for example, mixed amyloctyl, mixed ethoxy ethylamyland the like.

It is thus possible to produce esters which have desirable properties oftwo difierent alcohols embodied in the same product.

Certain mixed esters of a complex nature are also obtainable, forexample by esterifying ethylene oxide or similar alkylene oxides such aspropylene or butylene oxide with acids such as maleic acid and thenadding the sulpho group or by esterifying the sulphodicarboxylic aciddirectly with ethylene oxide.

While some of the most important esters of the present invention arethose with monohydric alcohols such as the ones enumerated above,important esters can also be obtained with polyhydric alcohols. Thus,for example, an ester may be obtained with glycerine which is watersoluble in the form of its alkali or ammonium salt. Ethylene glycol andother glycols such as propylene and butylene glycol produce new estershaving desirable properties, notably high solubility in water. Where apolyhydric alcohol is used such as glycerol, glycols, polyglycerols,pentaerythrite, and the like, part of the hydroxyl group only may beunited with the sulphodicarboxylic acid. Thus, for example, amonoglyceryl ester of sulphosuccinic acid may contain a free hydroxylgroup. If desired, this may be esterified with another acid. A furtherseries of mixed esters are obtained when the acid ester of a monohydricalcohol and a sulphodicarboxylic acid is caused to unite with one .ormore hydroxyls of a polyhydric alcohol. A large number of these mixedesters can be produced, some of which are resins of various types, andfor the most part they show solubility in water in the form of thealkali metal or ammonium salts.

Such esters of polyhydric alcohols which show Instead of esterifying acompound which is' v ticular importance.

purely a mono or polyhydric alcohol, esters can of course be producedfrom other compounds which contain hydroxyl groups. Thus, for example,ricinoleic acid or castor oil can be esterifled with asulphodicarboxylic acid to form a further series of esters having veryimportant wetting powers, particularly when the wetting agent has tubeused in alkaline solution. Such esters are, of course, also included inthe invention.

The most common esters of the present invention are those in which thesulphonic group of the acid is a single sulphonic group. It is, ofcourse, possible to esterify di and polysulpho acids with the productionof corresponding di and polysulpho esters, and such esters are of courseincluded 7 Most of the commercially useful esters are employed in theform of their alkali metal, usually sodium salts. For some purposes,however, it is undesirable to have an alkali metal present in thecompound and very eflectlve products are obtained in the form of saltswith ammonia or other amine basis, such as for example, triethanolamine,mono, di or trimethyl or ethyl amine, etc. It is also possible to formsalts of alkaloids and other organic basiscapable of salts formationwith the sulphonic group. Thus, for example,- salts with pyridine,nicotine, cinchona alkaloid and the like may be prepared and have theimportant advantage that they are readily applied in the form of aqueousdispersions because of the high wetting power of the esters of thesulpho acid. This permits the active organic base to be distributed inan aqueous material instead of a nonaqueous material, and is ofimportance in aiding the use of nicotineor Pyridine as an insecticide orcinchona alkaloids a's mothproofiing agents since they can be applied inaqueous dispersions instead of solutions in organic material which forsome purposes is a more desirable method of application. The applicationof certain basic dyes in the form of their salts with the sulpho estersis also important and such salts are likewise included.

The esters of the present invention possess two important propertieswhich render their use as wetting agents, detergents or emulsifiers ofpar- The first is their property of operating in hard water by reason ofthe great solubility of their calcium and magnesium salts. The secondproperty is their remarkable resistance to acid in which respect theyshow great superiority tonearly all wetting agents which have beendeveloped up to the present time.

Because of the large number of esters which can be prepared according tothe present invention, only a few are illustrated in the following isdescribed in a specific example as produced by a particular process,this does not limit this ester to production by the illustrated processas, in general, the esters can be produced by any of the alternativemethods which have been briefly described and which will be illustratedin greater detail in the specific examples.

Example 1 1 mol. of sulphomaleic acid in the form of its monosodium orpotassium salt is distilled with mols. of methyl alcohol, a small amountof sulphuric acid being added as an esterification catalyst. Thedistillate is fractionated under a reflux, water or aqueous methylalcohol is withdrawn from the system from the bottom of thefractionating column and the operation is continued until a conversionof or higher is obtained. The mixture A is ,then neutralized withcaustic soda or, if desired, with sodium carbonate and the excessalcohol is recovered by distillation.

The residual aqueous solution is evaporated to.

dryness and forms a white, rubbery acid having no definite melting pointand showing a very great solubility in water. sodium or potassium saltof dimethyl sulphomaleate.

Example 2 1 mol. of normal diamyl maleate having a boiling point from146 to 148 C. at 2' mms. is mixed with 1.05 mols. of sodium blsulphiteand the whole agitated at C. with water in the proportion of 100 partsby weight of water to 256 parts by weight of diamyl maleate. Preferablythe agita-, tion is carried out under slight pressure to avoid loss ofS02 and is continued until a sample is completely soluble in water. Themixture is dried and if required, freed from inorganic salts bydissolving in an organic solvent such as benzene, filtering andevaporating the benzene. The product, which is diamyl sulphosuccinate,is a transparent soapy solid which can be ground with some difliculty toa white powder. It is very-soluble in water, benzol, alcohol orgasoline. It is a wetting agent of great power and an excellentdetergent particularly because its calcium salt shows almost as muchsolubility as the sodium salt.

Example 3 340 parts of dioctyl fumarate (boiling point to C. at 4 mms.)is prepared by the esteriiication of fumaric acid with 2 ethyl hexanoland is mixed with 109 parts of sodium bisulphite and sufficient water toform a 50% solution. The addition of sodium bisulphiteis carried out asdescribed in Example 2 and the product purified in the same way. Theresulting sodium salt of dioctyl sulphosuccinate is a transparentrubbery mass which cannot be ground to a powder. It is soluble in waterand the common organic solvents, and shows a wetting power even greaterthan the diamyl sulphosuccinate. Instead of recovering the dioctylsulphosuccinate as described in Example 2, it may be salted out by anysuitable salt such as sodium chloride or sodium sulphate. Some of thesalt may be precipitated or retained by the dioctyl succinate and thisis unobjectionable since the addition of a certain amount of saltincreases the wetting power of this ester. The salt may have no wettingpower itself or the salt of another wetting agent such as, for example,the sodium salt of isopropylnaphthalene sulphonic acid may be added.Stitch mixed wetting agents are very useful for certain purposes.

The triethanolamine salt can be prepared by reacting with. triethanolamine hydrochloride and is likewise water soluble. Similarly saltscan beprepared with pyridine, nicotine, or cinchona alkaloid.

Example 4 a ,372 parts of the commercial mixed lauryl alcohols are mixedwith 242 parts of the disodium salt of sulphosuccinic acid, 50 parts ofsulphonic acid and 400 parts of toluene. distilled until approximately36* parts of water The product is the The mixture is Example 5 340 partsof dicapryl maleate are agitated with 109 parts of sodium bisulphite,dissolved in 100 parts of water until the reaction mixture is soluble inwater. Preferably the agitation is under slight pressure and at about100 C. as in the case of Example 2. The mixture is dried and purified bysolution in organic solvents as in Example '2, and the product which isdicapryl sodium sulphosuccinate is a transparent, rubbery substancewhich is considerably more soluble in water than the dioctylisomers. Thecorresponding ammonium salt can be readily prepared and is likewise verysoluble in water. Instead of purifying the dicapryl sulphosuccinate asdescribed in Example 2, it may be salted out as is described in Example3 and the presence of some additional salt improves the wetting power ofthe ester.

Example 6 242 parts of the disodium salt of suphosuccinic acid are mixedwith 462 parts of fenchyl alcohol and 500 parts of monochlor-benzene, 50

parts of sulphuric acid are added and the mix- 256 parts of the disodiumsalt of alpha sulphopyrotartaric acid which may be obtained by theaction of sodium sulphite on itaconic, citraconic or mesaconic acid aremixed with 270 parts of the ethyl ether of ethylene glycol andsuflicient sulphuric acid to combine with the sodium attached to thecarboxyl group oi the pyrotartaric acid and to liberate a little freesulphonic acid. The mixture is distilled until esterification iscomplete, the acid neutralized and the excess ethyl ether of ethyleneglycol removed by steam distillation. The residual sludge is thenevaporated to dryness and forms a jelly-like mass of sodiumdiethoxyethyl sulphopyrotartrate. The compound is very soluble in waterand shows good wetting powers.

Example 8 Maleic acid is esterified with the butyl ether of ethyleneglycol and 386 parts of the ester thus produced are sulphonated withsodium bisulphite as described in Example 2. The product, which is thesodium salt of the dibutoxy diethyl eneglycol sulphosuccinate, is verysimilar to that of Example '7.

Example 9 294 parts of crystalline dicyclohexyl glutaconate are producedby esterifying glutaconic acid with cyclohexanol, are mixed with 110parts of sodium bisulphite as a 50% aqueous solution, the mixture beingagitated at 100-110 C. until the whole is water soluble. 'I'hereupon 500parts of water are added, the mixture heated, filtered and allowed tocrystallize. The, resulting cyclohexyl ester of sulphoglutaric acid isquite crystalline, the substance having no definite melting point and isreadily soluble in water.

Example 10 '248 parts of monosodium salt of sulphoadipic acid areesterified with 324 parts of benzyl alcohol using the proceduredescribed in Example 6 but ,adding only 1 part of sulphuric acid toliberate a small amount of the free sulphonic acid to act as thecatalyst. The product after removing any excess alcohol, is the sodiumsalt of dibenzyl sulphoadipate, being a white powder soluble in water.

' Example 11 282 parts of the diphenyl ester of mesaconic acid(meltingpoint 66-67" C.) which may be obtained by heating mesaconic aciddichloride with sodium phenolate in toluene, are agitated for 24-48hours with 104-208 parts of sodium bisulphite as a 50% water solution.The agitation preferably takes place under pressure 'at somewhat above100 C. and is continued until the mixture is completely soluble inwater, whereupon toluene is added and the mixture distilled until allthe water is removed. The residual toluene is filtered and the tolueneevaporated leaving a white solid residue of sodium diphenylsulphopyrotartrate. The product is readily soluble in water from whichit may be crystallized on long standing.

Example 12 284 parts of the dimaleic ester of tetrahydrofurfuryl alcoholare agitated at 100-110 C. with 109 parts of sodium bisulphite in theform of a 50% aqueous solution. The product is then purified asdescribed in Example 2 and is an amorphous white solid possessing nodefinite melting point, being exceedingly soluble in water and organicsolvents. The product is the sodium salt of the ditetrahydrofurfurylester of sulphosuccinic acid.

Example 13 Sulphosuberic acid is prepared by sulphonating suberic acid,and 276 parts of the monosodium salt are esterified with a methylisobutyl carbinol. The excess alcohol is distilled off and the productwhich is the diester of sodium sulphosuberic acid with methyl isobutylcarbinol is a white solid which is very soluble in water.

Example 14 326 parts of the disodium salt of sulphosebacic acid isesterified with excess butyl alcohol and slightly more than mol. ofsulphuric acid for every molecule of the disodium sulphosebacate. Theexcess butyl alcohol is distilled oif and the dibutyl sodiumsulphosebacate is recovered as a white powder which is soluble in water.

Example 15 Distearyl maleate is prepared by esterifying a technicalalcohol containing stearyl alcohol as its main constituent with maleicanhydride, the esterification being carried out in a toluene solution.The crude product is recrystallized with benzol, and 124 parts of theester are heated at 100 C. for 24 hours with 42 parts of sodiumbisulphite and 40 parts of water, vigorous agitation being maintainedduring the heating. The product is then isolated and purified as inExample 2 and is a white, soapy powder, very slightly soluble in water.It constitutes the sodium salt of distearyl sulphosuccinate.

Example 16 Maleic acid is esterified with 'oleyl alcohol in the samemanner as described in Example 15.

124 parts of the ester are then heated at 100 C.

for about 24 hours with 42 parts of sodium bisulphite in 40 parts ofwater, vigorous agitation being continually maintained. The sodium saltof dioleyl sulphosuccinate is then isolated as described in Example 2and is a white soapy powder having a slight solubility in water.

Example 17 98 parts of maleic anhydride are heated with 40 parts ofethyl alcohol for about 1 hour, forming the acid ethyl ester of maleicacid. Thereupon 2'70 parts of stearyl alcohol are added together withsuflicient sulphuric acid to act as a catalyst. Then 250 parts oftoluene are added and the mixture slowly distilled until conversion tothe ethyl stearyl maleate is complete. 250 Darts of the 50% watersolution of sodium bisulphite are then added and the mixture is agitatedat 100 C. until a dried sample is soluble in water. The product, whichis the sodium salt of ethyl stearyl sulphosuccinate is a white powdershowing a moderate solubility in water. The solubility is very muchgreater than the distearyl ester and the product is usable as a wettingagent for various aqueous dispersions.

Example, 1 8

Example 19 Ethylene oxide and maleic acid are heated together to form acomplex ester. 180 parts of this reaction product are agitated at 100 C.with 150 parts of sodium bisulphite. The reaction proceeds rapidly andas soon as it is complete,

the mixture is evaporated to dryness and the product is separated fromexcess bisulphite by dissolving in boiling alcohol, filtering and.evaporating the filtrate. The ester of sulphosuccinic acid obtained is aglassy mass which is soluble in watenthe solubility depending to someextent on the-character of the ethylene oxide maleic acid reactionproduct.

Example 20 98 parts of maleic anhydride are heated with 130 parts ofoctyl alcohol at 120 C., producing the acid octyl maleate. 228 parts ofthis acid ester are then poured into a solution of 126 parts of sodiumsulphite in 1000 parts of water and the mixture stirred at 50 C. forsome minutes until a clear solution is obtained. This solution may beused as such or it may be evaporated to dryness, a white, amorphous,somewhat sticky product re maining, which is the disodium salt ofmonooctyl sulphosuccinate. The product is easily soluble in water.

Example 21 92 parts of glycerine and 98 parts of maleic anhydride areheated at 120 C. for 2 hours. The mixture is cooled to C. and pouredinto a solutlon of 104 parts of sodium bisulphite in 200 parts of water.The resulting mixture is then agitated for 2 hours at 80 C..andevaporated to dryness. A brittle, glassy mass which is the sodium saltof glycerol sulphosuccinate is obtained. It can be easily ground to awhite powder and is very soluble in water.

If ammonia bisulphite is used, the corresponding ammonium salt isproduced which is equally soluble in water.

Example 22 124 parts of ethylene glycol are heated at 120 C. for 2 hourswith 98 parts of maleic anhydride and the diglycol maleate so obtainedis poured into a solution of 104 parts or sodium bisulphite in 150 partsof water. The mixture is agitated at 60 C. until an acidifiedsampleliberates no S02 whereupon the solution is evaporated to dryness and theproduct may be ground to a. white powder which is exceedingly soluble inwater. The product obtained is the sodium salt of diglycolsulphosuccinate.

Example 23 184 parts of glycerine" are heated to 120 .C. for 1 hour with98 parts of maleic anhydride. 204 parts of acetic anhydride are slowlyadded, the temperature being maintained at 120 C. After all of theanhydride has been added the heating is continued for 2 more hours andthen the mixture is cooled at C. whereupon 1 10 parts of sodiumbisulphite in 150 parts of water are added and the mixture agitated in aclosed vessel at C. for 8 hours, or until the mixture is completelywater soluble. Thereupon the mixture is evaporated to dryness and asemitransparent gummy mass is obtained which is readily soluble inwater. It is the sodium salt of the glycerine ester of sulphosuccinicand acetic acids.

Example 24 92 parts of glycerine and 282 parts of oleic acid are heatedto 200 C. for 12 hours. The mixture is cooled to C. and 196 parts ofmaleic anhydride are added whereupon the heating is maintained for 3hours and then 400 parts of normal amyl alcohol and A part of sulphuricacid are added. The mixture is distilled until substantially 36 partsof, water have collected in the distillate, at'which time theesteriflcation is complete. The excess amyl alcohol is removed by steamdistillation and the residual'oil is agitated at 100 C. for 24 hourswith 250 parts-of sodium bisulphite. The solution is then evaporated todryness and a soft resin is obtained which is readily soluble in water.This would be probably as the following formula:

Example 25 88 parts of a primary amyl alcohol at about 100 C. for 2hours. The acid amyl phthalate obtained is then mixed with 92 parts ofglycerine and the mixture heated at -120 C. for four hours. The phthalicanhydride unites with one hydroxyi of the glycerine and the remaininghydroxyls of the glycerine are then esterified with 98 parts of maleicanhydride by heating at 120-140 C. for several hours. 'I'he'ester thusobtained is then sulphonated with 104 parts of sodium bisulphite'asdescribed in previous examples and recovered in the usual manner. Theglycerine ester of sulphosuccinic acid and acid amyl phthalate isobtained as a powder and is readily soluble in water. Instead ofphthalic anhydride other dibasic acids may be used such as succinicacid, chlormaleic acid, tartaric acid and the like.

Example 26 184 parts of glycerine are heated with 148 parts of phthalicanhydride at 130 C. for 4 hours. Thereupon 196 parts of maleic anhydrideare added in 1000 parts of tetraline. The mixture is slowly distilleduntil approximately 54 parts of water have been collected inthedistillate. Then the mixture is cooled to 80 C. At this stage mixedphthalic maleic ester of glycerine is ob tained. 208 parts of sodiumbisulphite dissolved in 300 parts of water are added and the mixtureagitated at 80 C. until a sample is completely water soluble. Thetetraline is removed by steam distillation and the aqueous solutionremaining filtered and dried, the residue is ground and constitutes aglyceryl phthalate' sulphosuccinate being a white powder very soluble inwater.

Instead of using phthalic anhydride monobasic acids such as benzoic acidor benzoylbenzoic ,acid can be employed in which case, of course,

the proportion of maleic acid is increased.

' Example 27 2 mols. of castor oil are esterified with 3 mols. of maleicanhydride resulting in a neutral ester in which the six hydroxyl groupsof the castor oil unite with the six hydroxyl groups of the maleic acid.This neutral ester is then treated with 3'mo1s. of sodium bisulphite totransform it into the corresponding sulphosuccinate. The product is notreadily soluble in water but can be rendered soluble by sulphonationwith sulphuric acid.

4 Example 28 An ester of maleic acid and castor oil is prepared butinstead of using 2 mols. of castor oil only 1 mol. is used. Aftertransformation into the. sulphosuccinate by means of, bisulphite, theproduct can be sulphonated with sulphuric acid or can be treated withcaustic alkali to increaseits water solubility.

What I claim is: I 1. An ester of an aliphatic dibasic acid having theiormula ooox COOX MoSOr-R COOX in which R is an aliphatic carbon chaincontaining at least one sulphonic group but free from othersubstituents, and X is hydrogen or an alcohol .or phenol radical notconnected by a carbon to carbon bond with R, at least one X being suchan alcohol or phenol radical, and Me is hydrogen or a base.

3. An ester of an aliphatic dibasic acid having the formula coox COOX inwhich R'is an aliphatic carbon chain containing at least one sulphonicgroup, but free fromother substituents, and X is an alcohol or phenolradical -not connected by a carbon to carbon bond with R.

4. An ester of an aliphatic dibasie' acid having the formula 5. An esterof an aliphatic dibasic acid having the formula I COOY in which R is analiphatic carbon chain containing at least one sulphonic group and freefrom mercapto groups and X is an alcohol or phenol radical and Y is adiiferent alcohol or phenol radical.

6. An ester of an aliphatic dlcarboxylic acid having the followingfarmula MoSOz-R in which R is a carbon chain freefrom mercapto groups,Me is a base, X is air-alcohol or phenol radical and Y is a differentalcohol or phenol radical.

7. An ester according to claim 2 in which Me is an organic amine base.

8. An ester of sulphosuccinic acid in which at least one carboxyl groupis united with the radical included in the group consisting 'ofalcohols, phenols.

9. An ester of sulphosuccinic acid in which each carboxyl group isjoined-to a radical included in the group consisting of alcohols,phenols.

10. An ester according to claim 9 in which alcohol or phenol radicalsattached to the different carboxyl groups are different.

11. A diamyl ester of sulphosuccinic acid.

12. A diester of sulphosuccinic acid and an octyl alcohol.

13. A method of producing an ester of a saturated sulphoaliphaticdicarboxylic acid which comprises producing the ester of thecorresponding unsaturated aliphatic ,dicarboxylic acid and reacting theester with a bisulphite.

14. A method of producing an ester of sulphosuccinic acid whichcomprises subjecting an ester of an acid included in the groupconsisting of maleic acid and fumaric acid to the action of abisulphite.

ALPHONS O. J AEGER.

